1. Field of the Invention
The present invention relates to an imaging apparatus and an imaging method, especially using, for example, a CMOS sensor in an imaging unit. More particularly, the invention is applicable as a monitoring apparatus. It can be also used as a parts inspection machine for electronic devices such as a liquid crystal device and a semiconductor device.
2. Description of the Related Art
As an imaging apparatus using photoelectric conversion elements, a CCD type imaging apparatus and a CMOS type imaging apparatus are known. In a CCD type imaging apparatus, photoelectric conversion elements are arrayed two-dimensionally, and imaging signals in field units are read out therefrom. In a CMOS type imaging apparatus, on the other hand, imaging signals in pixel units can be directly read out from photoelectric conversion elements arranged two-dimensionally.
Using such an imaging apparatus, a monitoring system or parts inspection system has been developed. In a conventional monitoring system or parts inspection system, imaging signals are read out from the entire surface of the imaging unit, and the imaging signals are transferred into a monitor or comparator circuit. In a monitoring system, the user checks the image on the monitor screen. In a parts inspection system, the comparator circuit compares a reference pattern and an image pattern of the imaging signal.
In the conventional monitoring system or parts inspection system, since the imaging signal is read out from the entire surface of the imaging unit, the reading time cannot be shortened, and when the imaging signal is converted from analog to digital, the data conversion quantity is a lot of. Accordingly, in the monitoring system, since the entire screen is always displayed, local checking of the image is difficult, and also in the parts inspection system, since the imaging signal of the entire screen is processed, it is hard to inspect at high speed.